Flux pinning in MOD YBCO films by chemical doping

A novel nanomaterial synthesis technique has been developed to introduce 0D (particles), 1D (columnar defects) and 3D (domains) nanoscale pinning centres in MOD Y₁Ba₂Cu₃O₇ (YBCO) coated conductors. We have succeeded in introducing nanoscale Y enriched particles, nanoscale 90° rotated Y_1/3Sm_2/3Ba₂Cu ₃O₇ domains and nanoscale Zr enriched columnar defects into YBCO layers by different chemical doping. The pinning force density in Y₂O₃-doped YBCO film is found to be larger than that of pure YBCO film at all fields. Also it was found that YBCO films with Sm substituting for Y have yielded improved critical current density characteristics over a wide range of magnetic fields. Maximum pinning force densities exceeding 7 and 8GNm^-3 are obtained in 5% BZO-doped and Sm substituted YBCO films, respectively. Additionally, TEM studies revealed nanoscale Zr enriched columnar defects distributing in the matrix of the c-oriented YBCO film throughout the whole cross section. This indicates that chemical doping is a promising fabrication technique to create specific pinning landscapes in YBCO coated conductors.